Image made from a video released by IS militants shows Steven Sotloff being held by the militant group.

The Islamic State released a video yesterday showing a masked militant beheading another American journalist and threatening to kill a British captive. The footage, identified by private terrorism monitor SITE and seen by AFP, shows 31-year-old freelance writer Steven Sotloff dressed in orange and on his knees in a desert landscape.

The masked militant condemns US attacks on the Islamic State and cuts Sotloff’s throat. He then introduces a second captive, identified as David Cawthorne Haines and said to be British. “I’m back, Obama, and I’m back because of your arrogant foreign policy towards the Islamic State … despite our serious warnings,” the militant says, in apparent reference to a previous video in which US journalist James Foley was murdered. “So just as your missiles continue to strike our people, our knife will continue to strike the necks of your people,” he said in the video entitled “A Second Message to America”.

White House spokesman Josh Earnest said he had not been aware of the report before taking the podium at his daily briefing, but added that the administration’s “thoughts and prayers” were with Sotloff’s family. A man who answered a phone listed in the name of Sotloff’s sister hung up when called by the AP.